1. Field of the Invention
The present invention relates to a pressure welding device for wiring and a wire harness manufacturing method for manufacturing a wire harness by integrally performing pressure welding and wiring.
2. Related Art
FIGS. 8 to 12 show a conventional wire harness manufacturing method.
In this method, small sub-wire harnesses 40, 43, 47, and 51 are provided as shown in FIGS. 9A to 9D, and a medium sub-wire harness 56 is also provided as shown in FIG. 10 (see steps 76 and 77 of FIG. 8).
The small sub-wire harness 40 shown in FIG. 9A is formed by pressure-welding wires 42 to two identical connectors 41. Each connector 41 is provided with a pressure welding terminal 55. The small sub-wire harness (a multiparallel wire harness) 43 shown in FIG. 9B is formed by pressure-welding wires 46 of the same length to a long connector 45 and two short connectors 45. The small sub-wire harness 47 shown in FIG. 9C is formed by pressure-welding wires 50 of different lengths to a long connector 48 to two short connectors 49 (49.sub.1 and 49.sub.2). The small sub-wire harness (a random harness) 51 shown in FIG. 9D is formed by pressure-welding crossed wires 54 to a long connector 52 and two short connectors 53.
The medium sub-wire harness 56 shown in FIG. 10 is formed by interposing an ECU (electronic control unit) 59 between connectors 57 and 58. The ECU 59 is equipped with a joint connector having pressure welding terminals 60.
The small sub-wire harnesses 40, 43, 47, and 51, and the medium sub-wire harness 56 are manufactured using a pressure welding unit 61 shown in FIG. 11. This pressure welding unit 61 is disclosed in Japanese Patent Application Laid-Open No. 6-31198 filed by the present applicant. The pressure welding unit 61 is provided with comb-like pressure welding blades 62 and 63 which are separately situated in the wire pulling direction, connector tables 64 and 65 which are situated below the respective pressure welding blades 62 and 63, and a pair of measurement rollers 66 interposed between the connector tables 64 and
The measurement rollers 66 and the rear-side pressure welding blade 63 are movable in the transverse direction. The measurement rollers 66 are rotated by a motor 67. Wires 68 are held by a feeding head 69 and fed to the connector tables 64 and 65. The feeding head 69 can move back and forth by virtue of a cylinder (not shown). The measurement rollers 66 may be positioned behind the connector table 65, and each pressure welding blade may take the form of a tooth as indicated by reference numeral 70 in FIG. 11, instead of the form of a comb.
With the pressure welding unit 61, the wires 68 are pressure-welded to a connector 71 placed on the front-side connector table 64. The connector 71 is then removed from the connector table 64, and as the wires 68 are measured for a predetermined length by the measurement rollers 66, the connector 71 is sent forward so as to pressure-weld the wires 68 to a connector 72 placed on the rear-side connector table 65.
The small sub-wire harness 47 shown in FIG. 9C is manufactured in the following manner. The short connectors 49 are set to the front-side connector table 64. Wires 50 (68) are pressure-welded to the short connector 49.sub.1, and subjected to measurement. The measurement rollers 66 are then moved in the transverse direction so as to pressure-weld the wires 50 (68) to the other short connector 49.sub.2. The small sub-wire harness 51 is manufactured using the single-tooth pressure welding blade 70 and moving the connector table 65 in the transverse direction.
The small sub-wire harnesses 40, 43, 47, and 51, and the medium sub-wire harness 56 are assembled on a wiring plate 73 and formed into a large sub-wire harness. The wiring plate 73 is provided with fork-like wiring fittings 75 standing at predetermined positions. The small sub-wire harness 47 and the medium sub-wire harness 56 are hooked by the wiring fittings 75 so as to form a wire harness. A continuity test is then conducted with a continuity checker (not shown) as in step 79 of FIG. 8. After the remaining necessary processes such as taping, a wire harness is finally completed.
With the above conventional wire harness manufacturing method, however, there is a problem that many processes are necessary because small sub-wire harnesses and a medium wire-harness are manufactured using a pressure welding unit, and then a large sub-wire harness is manufactured using a wiring plate.